Live portal: Go Live — browser window capture published over WHIP as <user>/HelmetCam-<date>; dumpd /me/stream-key

Go Live closes viewer windows, fetches the Authentik-identified user's MediaMTX key from dumpd
(/etc/vanguard/streamers.json written by configure.py), opens Chrome's window-only picker with
audio, prefers H.264 so MediaMTX can record, caps at 12 Mbps / 1440p60, shows live stats, Stop.

Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>

live/README.md

@@ -16,3 +16,12 @@ silences everything until you focus a window; "Follow focus" clears pins.
 
 Endpoints (proxied by Caddy, all behind the Authentik gate):
 `/api/*` → MediaMTX API 9997 · `/webrtc/*` → WebRTC/WHEP 8889 · `/hls/*` → HLS 8888.
+
+## Go Live (browser broadcast)
+Toolbar → **Go Live**: closes all viewer windows, fetches the logged-in user's stream key from
+`/me/stream-key` (dumpd, identity from Authentik's header), opens Chrome's window picker (windows only,
+audio requested), and publishes over WebRTC/WHIP to `<user>/HelmetCam-<date>` at ≤12 Mbps, H.264, up to
+1440p60. Recording, the "is live" post, the sweep and Jellyfin follow exactly as for an OBS stream.
+Window audio: Chrome on Windows. Linux/Mac: pick a tab or the whole screen for sound.
+Requires the Authentik username to equal the MediaMTX streamer name (configure.py keeps them in sync via
+`/etc/vanguard/streamers.json`).